Theory is important in guiding research to penetrate the bewildering surface of myriad age, sex, time and population-specific statistics about mortality at older ages. The goal of the proposed research is to advance theory and thereby empirical knowledge of mortality comparisons by using data from the "natural experiment" of East-West German unification and the resulting rapid convergence of E. German death rates to W. German levels to quantify the relative causal importance of two factors suggested by theory: "prosperity" vs. "healthcare".